While the computer industry has made clear progress in building smaller and lighter mobile platforms/devices (laptops, tablets, smartphones, etc.), alternating current (AC) adapters have not followed suit. One of the reasons for this is that AC adapters are specified to provide the highest power required by the platforms they support. If the platform requires more power than specified, the adapter will shut down. Most consumers feel that today's adapters are too bulky and should be smaller. This is particularly true for mobile platforms. The wide consumer adoption of Narrow Voltage Direct Current (NVDC) and Hybrid Power Boost (HPB) systems allows the adapters to be designed for smaller output power, because the battery can supplement the adapter if the platform power consumption exceeds the adapter capability. For example, a traditional laptop with a thermal design power (TDP) of 65 Watts (W) actually may consume an average power of much less than half of that.
An even more interesting situation arises for thin laptops that have low power consumption. Today it is common that even for these types of mobile platforms, adapters are commonly designed for 45 W of sustained power capability. Even though, in most cases, real life applications would require much less than 45 W, and a 12 W adapter may prove to be quite sufficient for most uses of platforms such as these. Moreover, some users may find it useful to purchase an adapter which is designed mostly for overnight charging of the laptop battery, while they expect to use the mobile platform while using the battery—a trend which should become more prevalent with longer battery run-time—analogous to today's cell phones, ebooks, and tablets. A small adapter may still support the normal operation of the system, but it may require the battery to cover the power spikes by supplementing the adapter with the battery. A small adapter may also allow the system to stay alive or discharge its battery much more slowly even at a heavy load.
As such, there is a demand for further reduction in the size of power adapters as well as a need for systems and power adapters to provide increasing performance to meet user expectations. Such problems may become critical as the desire to use mobile devices with ever increasing capabilities becomes more widespread.